How Much Paint Will I Need For The Exterior Of My House?

Painting the exterior of a house


How Much Paint For The Exterior Of A House 


Estimating how much paint you will need to paint the exterior of your house is a difficult task, especially for the average homeowner. Not having enough paint to complete the job could completely derail the project, as not only can it risk you having an uneven finish due to varying drying times of the paint, but the time it will take to find a dry day to begin the painting process again once you have ordered more paint could be huge. 


This considered, it is crucial to take the time to correctly estimate how much paint you will need before rushing into any painting. The amount of paint you will need depends on three things:


  • The size of your property
  • The coverage of the paint your are using
  • The number of coats required


By finding out the answer to these three factors, you will be able to correctly estimate exactly how much paint you will need.


The Size Of Your Property


Firstly, let's tackle the most crucial part of estimating how much paint you will. Estimating the size of a house is done in square metres, by measuring the length of the house, the height of the house and then estimating the size of doors and windows that will not be painted. There are a number of average sizes of houses, with a middle terraced house being 40m² on average, a 3 bed semi detached being 90m² and a 4 bed detached being 120m². Obviously, all houses are different and there is no one size fits all when it comes to estimating paint.


To work out the size of the exterior of your home, start being measuring the length of the property using a tape measure. If you are painting just part of the house, measure the length of just this section, if you are painting the full property, measure the full circumference of the house. For example, if you are painting all four walls of a detached house and each wall is 5 metres in length, your circumference will be 20m². Then work out the height of your property, either using a ladder and tape measure or simply by estimating. The average two-story house in the UK is 5 metres, although this can vary widely. 


If the height of your house is 5 metres for example, you then need to times this number by the total circumference of the property, which in our example is 20m². This gives you a rough figure as to the total area of the property, which would be 100m².


Finally, it is simply a case of establishing what parts of the property you are not planning to paint, such as windows and doors. An average window is roughly 1m², while a door is also 1m². Once you work out how much of the property you won't be painting, you know how big the area you are painting will be.


The Coverage Of The Paint Your Are Using


The coverage of masonry paint varies from paint to paint. A rough guide would be that the average masonry paint has a coverage of 8-10m² per litre on a smooth surface. While some paints are specifically designed to offer high coverage to save time, waterproof masonry paints such as Emperor Masonry Paint are designed to offer a coverage of between 5-6m² per litre in order to ensure they create a comprehensive protective coating.


It is important to remember that on very course surfaces such as pebbledash, the coverage of the paint will be half of what it is on a smooth masonry surface, giving you 3m² per litre with Emperor Masonry Paint. Furthermore, we are often asked whether you can thin down the first-coat of Emperor Masorny Paint to allow it is spread better to create a nice and even undercoat. The asnwer is yes, you can dilute Emperor Masonry Paint by 10%, which will give you a slightly higher coverage then if you did not dilute it. You do not have to dilute the first-coat however, and if you would like to ensure that you have an accurate estimation of how much paint you will need, we recommend you do not factor this into your calculations.


The Number of Coats Required


Finally, the number of coats a masonry paint will require can vary. Most masonry paints should coat a wall in two-coats, however this is not always the case, especially with standard retail paints. Emperor Masonry Paint while many people who use it say it completely coats the surface in one-coat, requires two-coats to fully waterproof the masonry. This is because a sufficent film must be built up by the paint in order to provide the waterproof, self-cleaning and excellent adhesion properties that Emperor Masonry Paint offers. If you coat the product with only one-coat, this film will not be built and therefore will not perform to the best of its ability.


The Total Amount Of Paint


So you have the total metres that you are painting, you know the coverage of the paint you will be using and you know how many coats of paint is recommended, it is now a case doing the maths.


A large 100m² detached property with eight windows and two doors will leave 90m² of exterior wall that will be painted, based off 1m² windows and doors. At 5m² per litre coverage on a smooth surface if you are using Emperor Masonry Paint, this equates to the need for 18 litres of paint to coat the exterior walls once. As a two-coat system, this is then simply doubled up, meaning a total 36 litres of paint will be needed to fully waterproof the property. 


This is a conservative calculation based off a large detached property. In reality, most properties will be middle terraces that will simply require no more than 40m² of exterior wall to be painted. If this is the case, two 10 litre tubs of Emperor Paint will be enough to protect & transform your home for 25+ years.


If you are unsure on how much paint you will need to buy to paint your house, you can either find our paint calculator on our help & advice page, that contains rough estimates depending on the size of your house, or you can get in touch with one of our experts who are on hand to help.


We hope that this article has answered some of your questions regarding how much paint you will require to paint the exterior of your house. Our team of experts are on hand to help you with any questions you may have as we know it can be a daunting task. If you would like to talk to one of the team, give them a ring on 0333 006 8880 or send an email to

Leave your comment
5/15/2022 8:57 AM
This article is most helpful. Did not realize the true significance of 2 or more coats. Thank you.